Tape for electric wire

ABSTRACT

A tape which has enhanced heat resistance, flame retardancy, and wearing resistance and is suitable for use in bundling a group of electric wires which will be laid in a high-temperature environment. The tape is configured using the same yarns ( 10 ) each composed of high-function fiber filaments ( 11 ) and general-purpose fiber filaments ( 12 ), as a warp ( 3 ) and a weft ( 4 ). The high-function fiber filaments are superior to the general-purpose fiber filaments in heat resistance, flame retardancy, and wearing resistance. The high-function fiber filaments are of at least one kind selected from paraaramid fibers, polyarylate fibers, ultrahigh-molecular polyethylene fibers, glass fibers, and polyphenylene sulfide fibers. The general-purpose fiber filaments comprise at least one selected from polyesters, polyethylene, and polypropylene.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a tape for electric wires and more particularly to a binding tape which can be preferably used as a tape to be wound around a group of electric wires of a wire harness to be wired on a vehicle.

2. Description of the Related Art

The tape disclosed in Japanese Patent Applications Laid-Open No. 2003-272447 and the like is conventionally used to bind and protect a group of electric wires of a wire harness to be wired on a vehicle and prevent the wire harness from interfering with external interference materials. An adhesive agent is applied to one surface of the tape. The tape is spirally wound around the peripheral surface of a wire harness W/H to bind the group of the electric wires.

Recently instead of the tape, a tube such as a corrugate tube is often used to bind and protect the group of the electric wires of the wire harness by inserting the group of the electric wires therethrough.

Because the corrugate tube is comparatively hard and heavy, the corrugate tube makes it less easy to perform a work of wiring the wire harness on the vehicle than the tape. In addition a slit is formed on the tube such as the corrugate tube in the axial direction thereof. After the group of the electric wires is inserted into the tube through the slit from the side of the corrugate tube, a tape is wound on the peripheral surface thereof to close the slit. Thus the use of the tube has a problem that the number of processes increases.

Therefore the use of the tape conventionally used is considered more useful than the tubes such as the corrugate tube.

As the wire harness-binding tape, a vinyl chloride tape is usually used. But as the tape for binding the wire harness to be wired on the vehicle, the vinyl chloride tape has room for improvement in its flame retardance, heat resistance, and wear resistance.

Although a tape consisting of braided polyester fibers is used as a heat-resistant tape from the above-described standpoint, the tape has low flame retardance and wear resistance. In addition there is a possibility that a cloth tape consisting of the polyester fibers hydrolyzes. Thus the tape consisting of the polyester fibers is unsuitable in using it inside an engine room.

SUMMARY OF THE INVENTION

The present invention has been made in view of the above-described problem. It is an object of the present invention to provide a tape for electric wires which has heat resistance, flame retardance, and wear resistance to such an extent that the tape can be used to bind a wire harness to be wired inside an engine room and is unlikely to hydrolyze.

To solve the above-described problem, the present invention provides a tape for electric wires, wherein the same yarns each consisting of high-function fiber strands and general-purpose fiber strands are woven by using the yarns as warps and wefts; the high-function fiber strands are superior to the general-purpose fiber strands in heat resistance, flame retardance, and wear resistance thereof; as the high-function fiber strands, at least one kind selected from among paraaramid fiber, polyarylate fiber, ultra-high-molecular-weight polyethylene fiber, glass fiber, polyphenylene sulfide fiber is used; and as the general-purpose fiber strands, at least one kind selected from among polyester, polyethylene, and polypropylene is used.

When resin fibers are used as the high-function fiber strands and the general-purpose fiber strands, resin not containing an electrically conductive component is used in the present invention. It is preferable to use halogen-free resin.

As described above, the yarn of the tape used in the present invention is composed of the high-function fiber strands superior to a tape formed by weaving polyester fibers conventionally used in heat resistance, flame retardance, and wear resistance thereof and the general-purpose fiber strands such as the polyester, the polyethylene, and the polypropylene mixed with the high-function fiber strands as the assistant fiber. The yarn to be used in the present invention has flame retardance and wear resistance improved over those of the yarn formed by weaving the general-purpose fibers. In addition the tape composed of the yarn has much less possibility of the occurrence of hydrolysis than the conventional tape formed by weaving the polyester fibers. Therefore the tape of the present invention can be used to bind the wire harness to be wired inside an engine room which is the most severe tape-using environment inside a vehicle.

Although there is a little difference in the heat resistance and the flame retardance in dependence on the kind of the high-function fiber strand used, the tape of the present invention is allowed to have higher heat resistance and flame retardance than the tape formed by weaving the polyester fiber.

It is favorable to set a mixing ratio of the high-function fiber strand to the general-purpose fiber strand to 10 to 50%:90 to 50%.

It is more favorable to set the mixing ratio of the high-function fiber strand to 20 to 30%.

The reason the mixing ratio of the high-function fiber strand is set to not less than 10% is because as described above, when the mixing ratio thereof is less than 10%, the flame retardance and wear resistance of the tape cannot be much improved. When the mixing ratio thereof exceeds 50%, the elongation, pull strength, and flexibility of the tape deteriorate and in addition the weight and cost thereof increase.

Each of the yarns is composed of a plurality of the high-function fiber strands and the general-purpose fiber strands arranged in the same direction; and the high-function fiber strands and the general-purpose fiber strands are arranged in parallel such that the one high-function fiber strand and the one general-purpose fiber strand alternate with each other or a plurality of the high-function fiber strands and a plurality of the general-purpose fiber strands alternate with each other.

It is preferable to alternately arrange the high-function fiber strands and general-purpose fiber strands. But when the mixing ratio of the high-function fiber strands is low, it is preferable to arrange the high-function fiber strands and the general-purpose fiber strands in such a way that a plurality of the general-purpose fiber strands is sandwiched between the high-function fiber strands.

To enhance the heat resistance and wear resistance of the general-purpose fiber strands, it is preferable to irradiate the formed tape with ionizing radiation to crosslink the general-purpose fiber strands.

It is possible to irradiate the general-purpose fiber strands with the ionizing radiation in advance and thereafter weave the general-purpose fiber strands and the high-function fiber strands.

To crosslink the general-purpose fiber strands with the ionizing radiation, it is preferable to add a crosslinking monomer to a resin component such as the polyester, the polyethylene, and the polypropylene and irradiate the general-purpose fiber strands with the ionizing radiation of not less than 100 kGy nor more than 400 kGy so that the general-purpose fiber strands are crosslinked at not less than 50% in a gel fraction (crosslinking rate).

The tape of the present invention is unlikely to hydrolyze. Therefore the tape can be used to bind a group of electric wires of the wire harness to be wired inside the engine room.

An adhesive agent is applied to one surface of the tape of the present invention to form the tape as an adhesive tape.

The adhesive agent may be entirely applied to one surface of the tape or continuously applied along one end or both ends thereof in its longitudinal direction.

The adhesive agent may be applied to both surfaces of the tape if necessary.

As described above, the tape of the present invention for electric wires is most favorably used as the tape for binding the group of the electric wires of the wire harness to be wired on a car. In addition the tape can be preferably used as a tape for binding a group of electric wires which are used in a condition similar to that of the wire harness for the car.

As apparent from the foregoing description, the tape of the present invention for electric wires is superior in its heat resistance, flame retardance, and wear resistance and rarely hydrolyzes. Therefore the tape can be preferably used as the tape for binding the group of electric wires of the wire harness to be wired on a vehicle and particularly inside the engine room.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a first embodiment of the present invention, in which 1(A) is an overall schematic view showing a state in which a tape of the present invention is wound around a wire harness, and 1(B) is a partly enlarged view.

FIG. 2(A) is a partly enlarged plan view of the tape, FIG. 2(B) is an enlarged view showing a yarn, and 2(C) is a schematic perspective view.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

A first embodiment of a tape of the present invention for an electric wire is described below.

As shown in FIG. 1(A), a tape 1 of the present invention for electric wires is used to bind the electric wires by spirally winding it around a peripheral surface of a wire harness 2, consisting of a group W of electric wires, which is to be wired on a car by means of half-wrap winding of overlapping the half of the width of a portion of the tape 1 to be wound on a wound portion thereof or wide-pitch winding as shown in FIG. 1(B). The tape 1 can be also used for partial winding of partially winding it around the group of the electric wires in the longitudinal direction thereof. The tape 1 is used for portions where conventional general-purpose tapes for electric wires are used.

As shown in FIG. 2(A) which is an enlarged view of the tape 1, the tape 1 consists of a cloth tape formed by weaving warps 3 and wefts 4. As shown in FIG. 2 (C) which is a schematic perspective view, an adhesive agent 5 is entirely applied to one surface of the tape 1.

The warps 3 and the wefts 4 consist of the same yarn 10 shown in FIG. 2(B). The tape 1 is formed by weaving the warps 3 and the wefts 4 by means of plain weave of interlacing them every one pitch in a lateral direction (course direction) of the tape 1 and a vertical direction (wale direction) thereof.

In the yarns 10 composing the warps 3 and the wefts 4, high-function fiber strands 11 and general-purpose fiber strands 12 are arranged in the same direction such that general-purpose fiber strands 12 are disposed at both sides of one high-function fiber strand 11 shown with thick solid lines. In the first embodiment, two general-purpose fiber strands 12 a, 12 b are sandwiched between the high-function fiber strands 11 a to form one group. The high-function fiber strands 11 and the general-purpose fiber strands 12 are arranged at a ratio of 1:2. Therefore the mixing ratio of the high-function fiber strands 11 to the general-purpose fiber strands 12 is set to 33%:66%.

One yarn 10 consists of 9 to 11 high-function fiber strands 11 and 19 to 21 general-purpose fiber strands 12. Thus the total of the high-function fiber strands 11 and the general-purpose fiber strands 12 are 28 to 32.

The high-function fiber strand 11 superior to the general-purpose fiber strand 12 in its heat resistance, flame retardance, and wear resistance is used. As materials for the high-function fiber strand, para-aramid fiber, polyarylate fiber, ultra-high-molecular-weight polyethylene fiber, glass fiber, and polyphenylene sulfide fiber are listed. Although one of these fibers is used in the first embodiment, a plurality of these fibers may be used. The para-aramid fiber is used in the first embodiment.

Although one kind selected from among polyester, polyethylene, and polypropylene is used as the general-purpose fiber strands 12, a plurality of these fibers may be used. The polyester fiber is used in the first embodiment.

The tape 1 formed by weaving the warps 3 and the wefts 4 consisting of the yarn 10 is unlikely to hydrolyzes.

The melting temperature of the tape 1 is set to not less than 120° C. to impart heat resistance thereto to such an extent that the tape 1 can be disposed inside an engine room of a vehicle.

The flame retardance of the tape 1 is set to be equivalent to V-0 in UL-94 of the flame retardance standards, and the oxygen index thereof (OI value) is set to not less than 23.5.

The wear resistance of the tape 1 is set to not less than 1000 mm in a tape wear test (load of 4.5N is applied to tape No. 150).

As described above, the tape 1 is formed by weaving the yarns 10 composed of the general-purpose fiber strand 12, consisting of polyester or the like, which is mixed with the high-function fiber strand 11 having heat resistance, flame retardance, and wear resistance superior to those of the general-purpose fiber strand 12 as the warps 3 and the wefts 4. Therefore the tape 1 can be used as a tape for binding the group of the electric wires of the wire harness to be wired in a high-temperature environment and wire harnesses to be wired on a trunk lid, a side door, a slide sheet and subjected to sliding.

Further because the tape 1 rarely hydrolyzes, the tape 1 can be preferably used as a tape for binding the group of the electric wires of the wire harness to be disposed inside the engine room.

Particularly the tape 1 has a simple configuration because the warps 3 and the wefts 4 are woven by means of plain weave. Thus the tape 1 can be easily produced by utilizing an existing facility. In addition by adjusting the mixing amount of the high-function fiber strand 11, heat resistance, flame retardance, and wear resistance can be easily imparted to the tape 1 to a demanded degree.

As apparent from the foregoing description, the tape 1 can be used at wiring portions of wire harnesses on which tubes such as the corrugate tube and the like and sheets are used instead of the vinyl chloride tape conventionally generally used. Therefore it is possible to decrease the number of parts, the cost, the weight of the entire wire harness including exterior materials, fuel consumption, and the maintenance cost of a vehicle.

The second embodiment is described below.

A tape of the second embodiment formed by weaving the warps and the wefts is irradiated with ionizing radiation to crosslink the general-purpose fiber strands consisting of the polyester fiber to allow the tape of the second embodiment to have a heat resistance higher than that of the tape 1 of the first embodiment and a melting temperature at 120° C.

The polyester fiber strand to be used as the general-purpose fiber strand is composed of a kneaded material containing polyester and 1 to 3 parts by weight of a crosslinking monomer consisting of triallyl isocyanurate or triallyl cyanurate added to 100 parts by mass of the polyester.

Yarns consisting of the general-purpose fiber strands and the high-function fiber strands similar to that of the first embodiment are woven by using the yarns as warps and wefts.

After the tape is formed by weaving the yarns, the tape is irradiated with the ionizing radiation having 100 kGy to 400 kGy to allow the polyester fiber strands to have a crosslinking rate not less than 50%.

Other constructions of the second embodiment are the same as those of the first embodiment. Therefore the same parts of the second embodiment as those of the first embodiment are denoted by the same reference numerals as those of the first embodiment, and the description of the constructions thereof is omitted herein.

When the melting point of the general-purpose fiber strand does not have a shape retention force in a temperature condition of an engine room, the tape of the second embodiment is irradiated with the ionizing radiation to crosslink the general-purpose fiber strand and raise the melting point thereof to impart the shape retention force to the tape. Further the tape is prevented from hydrolyzing. Therefore the tape of the second embodiment is useful for binding the electric wires of the wire harness to be wired inside the engine room.

It is possible to add a chemical crosslinking initiator to a resin component composing the general-purpose fiber strand to crosslink the general-purpose fiber strand. 

1. A tape for electric wires, comprising yarns, each of the yarns being formed from high-function fiber strands and general-purpose fiber strands, the yarns being woven by using said yarns as warps and wefts; said high-function fiber strands are superior to said general-purpose fiber strands in heat resistance, flame retardance, and wear resistance thereof; as said high-function fiber strands, at least one kind selected from among para-aramid fiber, polyarylate fiber, ultra-high-molecular-weight polyethylene fiber, glass fiber, polyphenylene sulfide fiber is used; and as said general-purpose fiber strands, at least one kind selected from among polyester, polyethylene, and polypropylene is used.
 2. A tape for electric wires according to claim 1, wherein a mixing ratio of said high-function fiber strands to said general-purpose fiber strands is 10 to 50%:90 to 50%.
 3. A tape for electric wires according to claim 1, wherein each of said yarns is composed of a plurality of said high-function fiber strands and said general-purpose fiber strands arranged in the same direction; and said high-function fiber strands and said general-purpose fiber strands are arranged in parallel such that said one high-function fiber strand and said one general-purpose fiber strand alternate with each other or a plurality of said high-function fiber strands and a plurality of said general-purpose fiber strands alternate with each other.
 4. A tape for electric wires according to claim 2, wherein said general-purpose fiber strands are irradiated with ionizing radiation to crosslink said general-purpose fiber strands.
 5. A tape for electric wires according to claim 1, wherein an adhesive agent is applied to one surface to form said tape as an adhesive tape.
 6. A tape for electric wires according to claim 2, which is used as a tape for binding a group of electric wires of a wire harness.
 7. The tape for electric wires according to claim 1, wherein an adhesive agent is applied to one surface to form said tape as an adhesive tape.
 8. The tape for electric wires according to claim 2, wherein an adhesive agent is applied to one surface to form said tape as an adhesive tape.
 9. The tape for electric wires according to claim 1, which is used as a tape for binding a group of electric wires of a wire harness.
 10. The tape for electric wires according to claim 2, which is used as a tape for binding a group of electric wires of a wire harness. 